Summary The Minnesota CHEAR Exposure Assessment Hub Targeted Analysis Resource will serve the research community by providing analyses of specific environmental stressors potentially affecting children's health. The investigators in this Resource have extensive experience in trace analytical chemistry and have developed many of the robust mass spectrometric methods for analysis of environmental toxicants and carcinogens that are standards in the field. This Targeted Analysis Resource maintains and operates 37 low and high resolution mass spectrometers and all related equipment necessary for high throughput analysis. This Resource will provide timely and reliable quantitative data relevant to 3 major areas of potential importance with respect to children's health: 1. Exposure to general environmental toxicants and carcinogens including urinary metabolites of polycyclic aromatic hydrocarbons, mercapturic acid metabolites of volatiles like butadiene, benzene, acrolein, crotonaldehyde, and ethylene oxide; urinary metals, bis-phenol A, the anti-microbial triclosan, and the insecticide aldicarb; serum polycyclics and volatile organic compounds, perfluorochemicals such as perfluorooctanoic acid, and mercury in dried blood spots. 2. Exposure to tobacco-specific compounds including urinary nicotine metabolites ? nicotine, cotinine, 3?- hydroxycotinine and their glucuronides, and nicotine-N-oxide; cotinine and 3?-hydroxycotinine in serum, dried blood spots, and toenails; the tobacco-specific carcinogen metabolites 4-(methylnitrosamino)-1-(3-pyridyl)-1- butanol in urine, blood, and toenails as well as its urinary glucuronides, and the tobacco-specific carcinogen metabolite N'-nitrosonornicotine and its glucuronides in urine. 3. Variations in levels of endogenous and dietary compounds such as the carcinogenic urinary heterocyclic aromatic amine combustion products 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline and 2-amino-1-methyl-6- pheynylimidazo[4,5-b]pyridine (PhIP) and their metabolites; urinary di-indolylmethane, a biomarker of cruciferous vegetable intake; and urinary polyphenols; PhIP in hair; as well as plasma carotenes, lycopenes, tocopherols, ascorbic acid, vitamin D, and fatty acids. We use highly structured sample acquisition and tracking systems as well as quality control procedures based on those required by the Centers for Disease Control and Prevention ?Demonstration of Analytical Performance? and the Food and Drug Administration ?Guidance for Industry Bioanalytical Method Validation.?